MEDLINE Journals

    Determination of water-soluble acid distribution in poly(lactide-co-glycolide).

    Ding AG, Schwendeman SP 
    J Pharm Sci 2004 Feb; 93(2) :322-31.

    Determination of the kinetics of water-soluble degradation products inside poly(lactide-co-glycolide) (PLGA) delivery systems during polymer degradation is important to evaluate the polymer microclimate conditions, particularly microclimate pH changes for optimization of encapsulated drug stability. A pre-derivatization high-performance liquid chromatography (HPLC) method was developed for separation and quantification of water-soluble acid impurities and degradation products in PLGA. Thin PLGA films (approximately 200 microm) were incubated in PBS/0.02% Tween 80, pH 7.4, for 6 weeks. Water-soluble monomers and oligomers were obtained from polymer films after repeated CHCl(3)/H(2)O extraction and then derivatized into bromophenacyl esters. With the common chromophore, the esters were separated and quantified by HPLC with increased ultraviolet (UV) sensitivity at 254 nm. The total amount of water-soluble acids in the extract was validated by potentiometric titration with tetrabutyl ammonium hydroxide. During the first 3 weeks of incubation of PLGA 50:50 (inherent viscosity = 0.63 dL/g), the principal water-soluble acids in the polymer were glycolic, lactic, and lactoyllactic acids, and an unknown oligomer. After 4 weeks of incubation, a large fraction of higher molecular weight oligomers was observed. Pre-derivatization HPLC can be used to accurately measure water-soluble acid distribution, and may be invaluable to examine the degradation behavior of PLGAs, including the underlying mechanism of polymer microclimate pH development.

    Chromatography, High Pressure Liquid
    Indicators and Reagents
    Lactic Acid
    Magnetic Resonance Spectroscopy
    Mass Spectrometry
    Membranes, Artificial
    Polyglycolic Acid
    Reference Standards


    Pub Type(s)
    Journal Article Research Support, U.S. Gov't, P.H.S.
    PubMed ID


    Content Manager
    Related Content

    Prediction of microclimate pH in poly(lactic-co-glycolic acid) films.

    Stability of proteins encapsulated in injectable and biodegradable poly(lactide-co-glycolide)-glucose millicylinders.

    Tetracycline-HCl-loaded poly(DL-lactide-co-glycolide) microspheres prepared by a spray drying technique: influence of gamma-irradiation on radical formation and polymer degradation.

    Co-effect of aqueous solubility of drugs and glycolide monomer on in vitro release rates from poly(D,L-lactide-co-glycolide) discs and polymer degradation.

    Physicomechanical properties of biodegradable poly(D,L-lactide) and poly(D,L-lactide-co-glycolide) films in the dry and wet states.

    Vancomycin release from poly(D,L-lactide) and poly(lactide-co-glycolide) disks.

    Characterization of degradation behavior for PLGA in various pH condition by simple liquid chromatography method.

    Porcine insulin biodegradable polyester microspheres: stability and in vitro release characteristics.